High Fuel Concentration Direct Liquid Fuel Cell with Redox Couple Cathode

Abstract

A unique approach which facilitates the use of high fuel concentrations in Direct Liquid Fuel Cells (DLFCs) is reported. By substituting the air cathode of a conventional DLFC with a redox couple cathode, a 3D carbon-based electrode can be employed to achieve cathode selectivity. This configuration not only eliminates cathode depolarization, but also enhances the cell design flexibility, allows for a Pt-free cathode and precludes cathode flooding as it is an all-liquid system. Methanol and formic acid are used as model fuels with the Fe2+/Fe3+ redox couple in cyclic voltammetry and fuel cell performance tests to demonstrate the positive attributes of this system. Fuel cell tests include the use of Nafion® 112 or Nafion® 117 as the membrane and fuel concentrations approaching that of pure fuel.